Limit

I took log with the base of 10 instead of ln
I've edited Skeeter's base e to base 10.
log10y=limx1log10(1+sin(πx))tan(πx)\displaystyle \log_{10}{y} = \lim_{x \to 1} \dfrac{\log_{10}(1+\sin(\pi x))}{\tan(\pi x)}

L’Hopital …

log10y=limx1πcos(πx)log(10)(1+sin(πx))πsec2(πx)\displaystyle \log_{10}{y} = \lim_{x \to 1} \dfrac{\frac{\pi \cos(\pi x)}{\log(10)(1+\sin(\pi x))}}{\pi \sec^2(\pi x)}

log10y=limx1cos3(πx)log(10)(1+sin(πx))=1log(10)\displaystyle \log_{10}{y} = \lim_{x \to 1} \dfrac{\cos^3(\pi x)}{\log(10)(1+\sin(\pi x))}= \frac{-1}{\log(10)}

y=101log(10)=1ey=10^{\frac{-1}{\log(10)}}=\frac{1}{e}
 
I've edited Skeeter's base e to base 10.
log10y=limx1log10(1+sin(πx))tan(πx)\displaystyle \log_{10}{y} = \lim_{x \to 1} \dfrac{\log_{10}(1+\sin(\pi x))}{\tan(\pi x)}

L’Hopital …

log10y=limx1πcos(πx)log(10)(1+sin(πx))πsec2(πx)\displaystyle \log_{10}{y} = \lim_{x \to 1} \dfrac{\frac{\pi \cos(\pi x)}{\log(10)(1+\sin(\pi x))}}{\pi \sec^2(\pi x)}

log10y=limx1cos3(πx)log(10)(1+sin(πx))=1log(10)\displaystyle \log_{10}{y} = \lim_{x \to 1} \dfrac{\cos^3(\pi x)}{\log(10)(1+\sin(\pi x))}= \frac{-1}{\log(10)}

y=101log(10)=1ey=10^{\frac{-1}{\log(10)}}=\frac{1}{e}
How did you get log after using L'Hopital. Doesn't it turn to xlna
 
How did you get log after using L'Hopital. Doesn't it turn to xlna
They are. Notice I didn't write log10(10)\log_{10}(10), but simply log(10)\log(10) which meant to be understood as loge(10)=ln(10)\log_{e}(10)=\ln(10)
 
Could you write this process a bit more detailed because I don't get it.
101ln10=10lneln10=10log10e=e110^{\frac{-1}{\ln 10}}=10^{\frac{-\ln e}{\ln 10}}=10^{-\log_{10}e}=e^{-1}Applying the change of base for log functions: logab=logcalogcb\log_{a}b=\frac{\log_{c}a}{\log_{c}b}
 
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